Vital Signs
FOCUS ON RECENT RESEARCH
This section includes brief accounts of selected Dartmouth research projects on biomedical and health-policy issues.
More on mad cow mutations
Yet another piece in the puzzle of prion diseases was reported recently by DMS's Surachai Supattapone, M.D., Ph.D. The October 16 issue of the journal Nature contained a paper on his team's discovery that RNA plays a role in converting a normal prion protein into a mutant that can lead to mad cow disease and other fatal brain illnesses. "It has been well proven that nucleic acids, including RNA, are not part of the infectious agent, so it's an ironic twist that a catalyst for the reaction may be RNA," says Supattapone. See the Fall issue of Dartmouth Medicine for details of another recent discovery by the team.
Not a blind alley
Retinitis pigmentosa is a degenerative eye disease that affects 1.5 million people worldwide. It is caused by a mutation in a photoreceptor that triggers a cascade of retinal changes, and it often leads to blindness by age 40. But DMS researcher John Hwa, M.D., Ph.D., has shown it may be possible to stop the changes that start in the photoreceptor rhodopsin, which detects low levels of light. "Basically, if we can stabilize the second domino after the first has fallen, we will be on our way to a cure for this disease," says Hwa.
Desperately seeking experienced surgeons
Seeking surgeons who perform a given procedure frequently appears to improve patients' odds of surviving major operations, according to a study led by DMS surgeon John Birkmeyer, M.D. The findings, reported in the New England Journal of Medicine, show that patients of high-volume surgeons have lower death rates even when the operation is done in a low-volume hospital, while those of low-volume surgeons have higher deaths rates no matter where the surgery takes place. The likelihood of death for low-volume surgeons' patients was as much as four times greater than for those of high-volume surgeons. The study was based on 474,000 Medicare patients who had one of eight commonly performed cardiac or cancer procedures.
Subtle but sobering news
Some sobering news was contained in a recent study of 32 female alcoholics. Women whose blood pressure rose even briefly when they quit drinking exhibited continuing cardiovascular problems weeks later, long after their blood pressure was back to normal. Unlike newly sober men, women appear not to show a sudden leap in blood pressure—but the effects in women last longer. The study was published in the journal Alcoholism: Clinical and Experimental Research. Lead author Nancy Bernardy, Ph.D., a research assistant professor of psychiatry at DMS, calls the differences "subtle but important." The next step, she says, is to see how long the effects last.
Racing to erase disparities in care
It's not news that there are racial disparities in the U.S. health-care system. But a recent study led by James Weinstein, D.O., chair of orthopaedics at DMS, has shown that when gender and geography are also added to the mix, the disparities are even greater. Published in the New England Journal of Medicine, the study was based on 430,000 total knee replacements. For example, says Weinstein, "while a black woman in Los Angeles is just as likely to have this operation as a white woman, a black man's chance of having the procedure is half that of his white counterpart."
Targeting the AIDS-TB combo
AIDS and TB are both serious diseases in their own right. Together, they're a lethal combination: Tuberculosis, according to the National Institute of Allergy and Infectious Disease, is "the major attributable cause of death" in patients with HIV/AIDS. But their weakened immune systems make the standard, live TB vaccine dangerous. So it was good news when an international team of researchers headed by DMS's Fordham von Reyn, M.D., announced an innovative killed-TB vaccine that appears to be effective and safe for AIDS patients. The strategy was reported in the journal AIDS.
What goes up can come down
Antipsychotic medications may be a godsend to the frame of mind for patients with depression, bipolar disorder, and schizophrenia— but not to their frame. Weight gain is a common side effect of such drugs. But now DMS psychiatrist Douglas Noordsy, M.D., has shown that such gains need not be permanent. He studied 35 patients taking an antipsychotic; they gained an average of 65 pounds over 33 months but were able to shed two-thirds of the increase three to five years later. The study was published in the Journal of Clinical Psychiatry. Noordsy told Reuters that the reason such a result hadn't been shown before is because most studies are too short-term.
Bad news about beta-carotene
Beta-carotene is not always beneficial, according to a recent study led by DMS epidemiologist John Baron, M.D. The vitamin A precursor has been shown to reduce the risk that colorectal polyps will recur and develop into cancerous tumors. But that finding does not pertain to those who smoke and drink regularly, Baron and colleagues recently determined. Paradoxically, in smokers and drinkers, beta-carotene more than doubled the incidence of polyp recurrence. The study was published in the Journal of the National Cancer Institute.